Biomedical subjects

G M Taylor

Publications and source records attributed to G M Taylor.

At least 19 recordsLinked to original sources

PubMed2006

Genotoxicity of etoposide: greater susceptibility of MLL than other target genes.

The ability of topoisomerase 2 inhibitors to induce DNA breakage is well recognized. Previous studies, however, have concentrated on the effects on individual genes. The effects of etoposide on the MLL, RUNX1, and MLLT3 genes were simultaneously studied in the same hemopoietic cell population. We found MLL to be more susceptible to etoposide-induced cleavage than RUNX1 and MLLT3, with maximum cleavage at a lower drug concentration. A higher level of MLL than other gene cleavage was also detected after cellular exposure to all drug concentrations. Greater susceptibility to topoisomerase 2 inhibitor-induced cleavage may explain the more frequent involvement of MLL in treatment-related leukemogenesis.

Core Binding Factor Alpha 2 Subunit↗

PubMed2005

Effects of topoisomerase 2 inhibitors on the MLL gene in children receiving chemotherapy: a prospective study.

The molecular effects of etoposide in haemopoietic cells suggest that mixed lineage leukaemia (MLL) abnormalities can be biomarkers of patient susceptibility to the genotoxic effects of topoisomerase 2 (topo 2) inhibitors. We have prospectively studied treatment-related MLL cleavage and rearrangement in serial samples from 71 children receiving chemotherapy, using Southern blot analysis and panhandle PCR. The results were related to patient demographics, treatment details and outcome. MLL cleavage was identified in six bone marrow samples from five patients 2-10 months after the start of therapy. There was no obvious relationship between the degree of MLL cleavage and cumulative dose or schedule of topo 2 inhibitors. Three children with low percentage (23-30%) cleavage remained well and two were still receiving treatment at study completion. One child with two consecutively positive samples and higher level of MLL cleavage (45-48%) died from treatment-related toxicities and relapsed leukaemia. A patient with haemophagocytic lymphohistiocytosis developed the highest level of MLL cleavage (50%) at 3 months and a treatment-related leukaemia with MLL rearrangement 6 months after the start of treatment. It would appear that some patients are inherently more susceptible to the genotoxic effect of topo 2 inhibitors. The degree and persistence of MLL cleavage may identify patients at risk.

Adolescent↗

PubMed2005

Effect of IL-6 promoter polymorphism on incidence and outcome in Hodgkin's lymphoma.

A single nucleotide polymorphism (SNP) is present at position -174 of the human interleukin-6 gene. The risk of developing Hodgkin's lymphoma (HL) in young adults decreases with an increasing number of C alleles at this position. We analysed the effect of this SNP on incidence and outcome in HL. DNA samples from 408 cases and 349 controls were screened and analysed following stratification by age, histological subtype and Epstein-Barr virus status. Although the risk of classical HL in young adults decreased with increasing C alleles, case-control differences were not significant. An excess of G alleles was observed for nodular lymphocyte predominant HL in young adults (n = 21), which was significant.

Adolescent↗

PubMed2004

Coexistence of treatment-related MLL cleavage and rearrangement in a child with haemophagocytic lymphohistiocytosis.

Treatment-related acute myeloid leukaemia (t-AML) is a serious complication of topoisomerase 2 inhibitor therapy and is characterised by the presence of mixed lineage leukaemia (MLL) rearrangement. By molecular tracking, we were able to show that MLL cleavage preceded gene rearrangement by 3 months and before the clinical diagnosis of t-AML in a patient with haemophagocytic lymphohistiocytosis. This is the first report on the sequential detection of the two biomarkers in treatment-related leukaemogenesis.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2003

Koch's bacillus - a look at the first isolate of Mycobacterium tuberculosis from a modern perspective.

Using molecular methods the authors have studied mycobacterial DNA taken from a 19th century victim of tuberculosis. This was the case from which Robert Koch first isolated and cultured the organism responsible for tuberculosis. The mycobacteria were preserved within five glass culture tubes as abundant bacterial colonies on slopes of a gelatinous culture medium of unknown composition. Originally presented by Koch to surgical laryngologist Walter Jobson Horne in London in 1901, the relic has, since 1983, been in the care of the Royal College of Surgeons of England. Light and electron microscopy established the presence of acid-fast mycobacteria but showed that morphological preservation was generally poor. Eleven different genomic loci were successfully amplified by PCR. This series of experiments confirmed that the organisms were indeed Mycobacterium tuberculosis and further showed that the original strain was in evolutionary terms similar to 'modern' isolates, having undergone the TB D1 deletion. Attempts to determine the genotypic group of the isolate were only partially successful, due in part to the degraded nature of the DNA and possibly also to a truncation in the katG gene, which formed part of the classification scheme. Spoligotyping resulted in amplification of DR spacers consistent with M. tuberculosis but with discrepancies between independent extracts, stressing the limitations of this typing method when applied to poorly preserved material.

Bacteriology↗

PubMed2003

Absence of leukaemic fusion gene transcripts in preterm infants exposed to diagnostic x rays.

BACKGROUND: Childhood leukaemias express novel, clonotypic fusion genes that may already be present at birth before the clinical manifestation of leukaemia. Exposure of the fetus to diagnostic x rays is reported to increase the risk of childhood leukaemia, and may do so by generating leukaemic fusion genes. Advances in neonatal medicine in the past decade that have extended the limits of viability of preterm babies down to 23 weeks of gestation have resulted in the increased use of diagnostic x rays to monitor neonatal progress. AIM: To investigate whether exposure of very preterm infants to diagnostic x rays in the neonatal period leads to the development of leukaemic fusion genes. METHODS: Peripheral blood samples were collected at birth from very preterm infants (23-30 weeks gestation) and following exposure to diagnostic x rays at intervals of two weeks, until discharge. Cord blood samples from normal full term infants served as controls. Total RNA was extracted from the blood and the expression of the fusion genes TEL-AML1, MLL-AF4, and BCR-ABL, characteristic of three subtypes of childhood leukaemia, was investigated in the preterm and full term infant samples using a nested reverse transcriptase polymerase chain reaction method. Serial pre- and post-x ray samples from 42 preterm babies, pre-x ray samples from an additional 46 preterm infants, and cord blood samples from 100 normal full term infants were screened for fusion gene transcripts. RESULTS: No leukaemic fusion gene transcripts were detected in preterm infants following exposure to diagnostic x rays. A BCR-ABL transcript was identified in a single preterm infant prior to x ray exposure. TEL-AML1 transcripts were detected in cord blood samples from two full term infants. MLL-AF4 transcripts were not detected in any of the pre- or full term infants tested. CONCLUSIONS: Exposure of the preterm infants to x rays in this small series and at the doses used for diagnostic purposes did not induce leukaemic fusion gene expression, but we cannot exclude the possibility that a small proportion of preterm infants may be unusually sensitive to x rays.

Cell Line↗

PubMed2003

The Scotland and Newcastle epidemiological study of Hodgkin's disease: impact of histopathological review and EBV status on incidence estimates.

AIMS: The epidemiological and pathological features of Hodgkin lymphoma (HL) are complex. The Epstein-Barr virus (EBV) is consistently associated with a proportion of cases, and these cases are thought to represent a distinct aetiological subgroup of HL. The aim of the present analysis was to determine the age and sex specific incidence of EBV associated and non-associated HL, analysed separately, using data derived from a population based study-the Scotland and Newcastle epidemiological study of Hodgkin's disease (SNEHD). This study also provided a unique opportunity to evaluate accuracy in the current diagnosis and classification of HL. METHODS: SNEHD analysed consecutive cases of HL diagnosed in the study area between 1993 and 1997. Diagnostic biopsy material was retrieved, EBV status of tumours was determined, and histological review was performed. RESULTS: In total, 622 cases were eligible for the study, and EBV studies and histopathological review were performed on biopsy material from 537 and 549 cases, respectively. Accuracy in the overall diagnosis of HL and classification of nodular sclerosis HL was good, but diagnosis of HL in the elderly and classification of other subtypes was less reliable. One third of classic HL cases were EBV associated, and age specific incidence curves for EBV associated and non-associated cases were distinct. CONCLUSIONS: Comparison of age specific incidence curves for EBV associated and non-associated HL supports the hypothesis that these are two distinct aetiological entities. Accuracy in the diagnosis of HL is generally good, but certain subgroups of cases continue to present diagnostic difficulties.

Adolescent↗

PubMed2003

Association of acute parvovirus B19 infection with new onset of acute lymphoblastic and myeloblastic leukaemia.

AIMS: To investigate the association of acute parvovirus B19 infection with new onset of acute lymphoblastic and myeloblastic leukaemia. METHODS: Cerebrospinal fluid (CSF) samples from patients with acute myelogenous leukaemia (AML) at diagnosis (n = 2) and acute lymphoblastic leukaemia (ALL) at diagnosis (n = 14) were analysed for parvovirus B19 DNA by means of nested polymerase chain reaction. In addition, samples from patients with benign intracranial hypertension (BIH) (n = 10) and hydrocephalus (n = 13) were tested as controls. RESULTS: Four leukaemia cases were positive-common ALL (n = 2), null cell ALL (n =1), and M7 AML (n = 1)-whereas all controls were negative (Yates corrected chi(2) value, 3.97; p = 0.046; odds ratio, 16.92; confidence interval, 1.03 to 77.18). All four patients were significantly anaemic, but none was encephalitic or had evidence of central nervous system leukaemia. In three of these patients, serum tumour necrosis alpha, interferon gamma, interleukin 6, granulocyte-macrophage colony stimulating factor (range, 34.93-3800.06 pg/ml), and macrophage chemoattractant protein 1 were detectable. All of these four patients carried at least one of the HLA-DRB1 alleles, which have been associated with symptomatic parvovirus B19 infection. CONCLUSION: Erythroid suppression and immune cell proliferation are both associated with B19 infection and may also be important in the pathogenesis of acute leukaemia.

Acute Disease↗

PubMed2002

An infectious aetiology for childhood brain tumours? Evidence from space-time clustering and seasonality analyses.

To investigate whether infections or other environmental exposures may be involved in the aetiology of childhood central nervous system tumours, we have analysed for space-time clustering and seasonality using population-based data from the North West of England for the period 1954 to 1998. Knox tests for space-time interactions between cases were applied with fixed thresholds of close in space, <5 km, and close in time, <1 year apart. Addresses at birth and diagnosis were used. Tests were repeated replacing geographical distance with distance to the Nth nearest neighbour. N was chosen such that the mean distance was 5 km. Data were also examined by a second order procedure based on K-functions. Tests for heterogeneity and Edwards' test for sinusoidal variation were applied to examine changes of incidence with month of birth or diagnosis. There was strong evidence of space-time clustering, particularly involving cases of astrocytoma and ependymoma. Analyses of seasonal variation showed excesses of cases born in the late Autumn or Winter. Results are consistent with a role for infections in a proportion of cases from these diagnostic groups. Further studies are needed to identify putative infectious agents.

Adolescent↗

PubMed2002

Investigation of the link between visceral surface rib lesions and tuberculosis in a Medieval skeletal series from England using ancient DNA.

Seven human skeletons from a large assemblage from a rural English Medieval burial site show lesions, predominantly proliferative in nature, on the visceral surfaces of the ribs. In order to investigate whether these rib lesions were regularly associated with tuberculous infection, these individuals, together with a group of age- and sex-matched control skeletons without bony signs of infection, were subjected to polymerase chain reaction (PCR) assays aimed at detecting traces of DNA from infecting microorganisms of the Mycobacterium tuberculosis complex. The results provided no evidence for any regular association between visceral surface rib lesions and the presence of M. tuberculosis complex DNA in the study group. The significance of these findings for the paleopathological interpretation of visceral surface rib lesions is discussed.

Adolescent↗

PubMed2002

Genetic susceptibility to Hodgkin's lymphoma and to secondary cancer: workshop report.

Although the occurrence of familial Hodgkin's lymphoma (HL) is a rare event, genetic susceptibility as a cause of HL and its influence on treatment outcome may not be rare. However, results obtained from the analysis of HL families will probably have broad implications with regard to understanding common pathogenic factors leading to the development of the disease. The description of anticipation among the affected offspring of HL patients further strengthens the view that heritable factors contribute to development of HL. Moreover, the finding that particular human leukocyte antigen (HLA) alleles are associated with susceptibility to HL may be regarded as a hint to the presence of an as yet undefined infectious agent, leading to the growth of a malignant lymphoma cell clone in those patients that are more susceptible to this agent due to their HLA genotype. In addition, since an intrinsic genomic instability was observed in a proportion of HL patients, it is plausible that these patients are not only susceptible to the causation of HL, but are also at a higher risk of developing therapy-related (TR) secondary cancers following treatment. Estimation of sister chromatid exchange was established as a tool to identify patients at higher risk of TR cancer. In this context the use of therapeutic agents known to increase genomic instability should be carefully considered prior to determing the best treatment. The future identification of heritable factors contributing to HL will be of importance both with regard to diagnosis as well as treatment of HL patients.

Age of Onset↗

PubMed2002

Antenatal steroids are associated with a reduction in the incidence of cerebral white matter lesions in very low birthweight infants.

AIMS: To investigate whether antenatal steroids reduce the incidence of cerebral white matter lesions in very low birthweight infants. METHODS: A total of 224 newborn infants of < 31 weeks gestational age and weighing < 1500 g was studied between January 1998 and June 2000. Obstetric and neonatal information was obtained from the case notes. The study population was subdivided into two groups according to antenatal steroid exposure. A complete course of treatment consisted of two doses of 12 mg each of betamethasone given at an interval of 12-24 hours. Infants in group 1 were born to mothers who had not received betamethasone, or were delivered within 24 hours of receiving the first dose of steroid. Infants in group 2 were born to mothers who had received one or more complete courses of betamethasone and were delivered > 24 hours after receiving the first dose of steroid. RESULTS: The two groups contained statistically similar proportions of boys and girls, and the infants had similar birth weights and survival rates. Those in group 2, compared with those in group 1, had a lower gestational age (p = 0.02) and a lower incidence of white matter lesions on cranial ultrasound scans (p = 0.03). Stepwise logistic regression analysis showed that gestational age (p = 0.0002) and a complete course of antenatal steroids (p = 0.02) had independent effects on cerebral white matter lesions. CONCLUSIONS: These observations suggest that a complete course of antenatal steroids may have a protective effect against cerebral white matter lesions in very low birthweight infants.

Analysis of Variance↗

PubMed2001

Temporal increases in the incidence of childhood solid tumors seen in Northwest England (1954-1998) are likely to be real.

BACKGROUND: There has been speculation that increasing trends in incidence of childhood central nervous system tumors and infant neuroblastoma in the United States have been due to diagnostic improvements or reporting changes. To investigate whether or not such trends could be explained in this way in the U.K., the authors used population-based data from Northwest England to analyze incidence trends in childhood solid tumors. METHODS: Cases were diagnosed during 1954-1998 and were grouped according to a morphology-based classification scheme. More than 95% of diagnoses were based on special histopathologic review. Tissue sections were retained, and diagnoses were rereviewed to ensure consistency in classification throughout the time period. Age-, gender- and period-specific incidence rates were calculated. Analyses were performed with chi-square tests and Poisson regression. RESULTS: There was an overall increase in the incidence of all childhood solid tumors of 0.9% each year. A temporal increase was found in childhood brain tumors characterized by, in particular, annual increases of 1% in pilocytic astrocytoma, 1% in primitive neuroectodermal tumors, and 2.3% in miscellaneous gliomas. The incidence of germ cell tumors increased at a rate of 2.6% each year. CONCLUSIONS: These increases could not be attributed to changes in diagnostic practice, and it is unlikely that the increases were due to changes in reporting practice. Further, the restriction of the increases to certain groups, with stable rates in others, argued against the changes being artifactual. The authors concluded that the increases in incidence were likely to be real.

Central Nervous System Neoplasms↗

PubMed2001

Molecular tracking of leukemogenesis in a triplet pregnancy.

The occurrence of childhood acute lymphoblastic leukemia (ALL) in 2 of 3 triplets provided a unique opportunity for the investigation of leukemogenesis and the natural history of ALL. The 2 leukemic triplets were monozygotic twins and shared an identical, acquired TEL-AML1 genomic fusion sequence indicative of a single-cell origin in utero in one fetus followed by dissemination of clonal progeny to the comonozygotic twin by intraplacental transfer. In accord with this interpretation, clonotypic TEL-AML1 fusion sequences could be amplified from the archived neonatal blood spots of the leukemic twins. The blood spot of the third, healthy, dizygotic triplet was also fusion gene positive in a single segment, though at age 3 years, his blood was found negative by sensitive polymerase chain reaction (PCR) screening for the genomic sequence and by reverse transcription-PCR. Leukemic cells in both twins had, in addition to TEL-AML1 fusion, a deletion of the normal, nonrearranged TEL allele. However, this genetic change was found by fluorescence in situ hybridization to be subclonal in both twins. Furthermore, mapping of the genomic boundaries of TEL deletions using microsatellite markers indicated that they were individually distinct in the twins and therefore must have arisen as independent and secondary events, probably after birth. These data support a multihit temporal model for the pathogenesis of the common form of childhood leukemia.

Base Sequence↗

PubMed2001

Methylenetetrahydrofolate reductase (MTHFR) polymorphisms and risk of molecularly defined subtypes of childhood acute leukemia.

Low folate intake as well as alterations in folate metabolism as a result of polymorphisms in the enzyme methylenetetrahydrofolate reductase (MTHFR) have been associated with an increased incidence of neural tube defects, vascular disease, and some cancers. Polymorphic variants of MTHFR lead to enhanced thymidine pools and better quality DNA synthesis that could afford some protection from the development of leukemias, particularly those with translocations. We now report associations of MTHFR polymorphisms in three subgroups of pediatric leukemias: infant lymphoblastic or myeloblastic leukemias with MLL rearrangements and childhood lymphoblastic leukemias with either TEL-AML1 fusions or hyperdiploid karyotypes. Pediatric leukemia patients (n = 253 total) and healthy newborn controls (n = 200) were genotyped for MTHFR polymorphisms at nucleotides 677 (C-->T) and 1,298 (A-->C). A significant association for carriers of C677T was demonstrated for leukemias with MLL translocations (MLL+, n = 37) when compared with controls [adjusted odd ratios (OR) = 0.36 with a 95% confidence interval (CI) of 0.15-0.85; P = 0.017]. This protective effect was not evident for A1298C alleles (OR = 1.14). In contrast, associations for A1298C homozygotes (CC; OR = 0.26 with a 95% CI of 0.07--0.81) and C677T homozygotes (TT; OR = 0.49 with a 95% CI of 0.20--1.17) were observed for hyperdiploid leukemias (n = 138). No significant associations were evident for either polymorphism with TEL-AML1+ leukemias (n = 78). These differences in allelic associations may point to discrete attributes of the two alleles in their ability to alter folate and one-carbon metabolite pools and impact after DNA synthesis and methylation pathways, but should be viewed cautiously pending larger follow-up studies. The data provide evidence that molecularly defined subgroups of pediatric leukemias have different etiologies and also suggest a role of folate in the development of childhood leukemia.

Adolescent↗

PubMed2001

Paleopathological and biomolecular study of tuberculosis in a medieval skeletal collection from England.

Nine human skeletons of medieval date from a rural English burial site show signs of skeletal tuberculosis. They were subject to polymerase chain reaction (PCR) assays aimed at detecting traces of DNA from infecting mycobacteria, with the purpose both of confirming the paleopathological diagnosis of tuberculosis and determining in individual cases whether disease was due to M. tuberculosis or M. bovis. In all nine cases, evidence for M. tuberculosis complex DNA was found, and in all instances it appeared that disease was due to M. tuberculosis rather than M. bovis. The significance of the findings for understanding tuberculous infection in rural agrarian communities in medieval England is discussed.

Adult↗

PubMed2001

Pulmonary artery occlusion from tuberculous lymphadenopathy in a child.

Occlusion of the pulmonary artery is a rare complication of mediastinal tuberculosis. We report on a 10-year-old girl who presented with a tuberculous pericardial effusion in whom subsequent imaging showed a totally occluded right pulmonary artery from tuberculous lymphadenopathy. Diagnosis was confirmed by polymerase chain reaction from a lymph node biopsy. Failure of medical therapy necessitated surgical reconstruction of her right pulmonary artery. Postoperatively she has normal perfusion of the right lung and normal lung function.

Arterial Occlusive Diseases↗

PubMed2001

Examination of temporal trends in the incidence of childhood leukaemias and lymphomas provides aetiological clues.

The age-sex distributions and temporal trends in incidence of leukaemia and lymphoma from the Manchester Children's Tumour Registry (MCTR), 1954-1998, are reported. This 45-year study includes 1795 children, all of whom had a histologically and/or cytologically verified leukaemia or lymphoma. At the time of their diagnoses all the children were under 15 years of age and were resident in a geographically defined area of northwest England covered by the MCTR. Log-linear modelling identified significant linear increases in acute lymphoblastic leukaemia (ALL) (average annual increase 0.7%; P= 0.005) and in Hodgkin's disease (HD) (1.2%, P=0.04), but not in acute myeloid leukaemia (AML), nor in non-Hodgkin's lymphoma (NHL). The increase in ALL was most pronounced amongst males, aged 1-4 years, and is likely to be due to precursor B-cell leukaemias. The increases in ALL and HD are discussed in relation to current hypotheses suggesting a role for infection. Additionally, a non-linear cohort effect was identified for NHL (P= 0.008), which may indicate the involvement of environmental factors other than infection.

Acute Disease↗